Gold catalysts have become an established and widely used tool for the functionalization of unsaturated hydrocarbons such as alkenes, alkynes, or allenes. Under very mild conditions these substrates are activated towards the attack of various nucleophiles leading to a plethora of synthetically useful building blocks. In contrast, corresponding methods employing optically active gold catalysts for the synthesis of enantiomerically enriched products are far more limited in number and their applications mostly focus on allenes and enynes. In particular terminal alkynes have challenged gold catalysts based on chiral phosphine or carbene ligands leading to products with only moderate enantioselectivities due to the linear coordination geometry in gold(I) alkyne complexes. We have developed an enantioselective cycloisomerization of diynes using gold catalysts incorporating chiral anions. The heterocyclic products incorporate an all-carbon quaternary stereocenter serving as intermediates for the construction of alkaloid natural products.

Enantioselective functionalization of terminal alkynes by gold catalysis

246th National Meeting (2013)

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